[转贴] 脑洞清奇的批处理多行注释

CrLf

很有意思，但是因为依赖 goto，所以效率比较低，不建议用在 for 里

https://stackoverflow.com/questions/8526946/commenting-multiple-lines-in-dos-batch-file/28522310#28522310
 
The update in the dbenham's answer gave me some ideas. First - there are two different cases where we can need multi line comments - in a bracket's context where GOTO cannot be used and outside it. Inside brackets context we can use another brackets if there's a condition which prevents the code to be executed.Though the code thede will still be parsed and some syntax errors will be detected (FOR,IF ,improperly closed brackets, wrong parameter expansion ..).So if it is possible it's better to use GOTO.
 
Though it is not possible to create a macro/variable used as a label - but is possible to use macros for bracket's comments.Still two tricks can be used make the GOTO comments more symetrical and more pleasing (at least for me). For this I'll use two tricks - 1) you can put a single symbol in front of a label and goto will still able to find it (I have no idea why is this.My guues it is searching for a drive). 2) you can put a single : at the end of a variable name and a replacement/subtring feature will be not triggered (even under enabled extensions). Wich combined with the macros for brackets comments can make the both cases to look almost the same.
 
So here are the examples (in order I like them most):
 
With rectangular brackets:
 
@echo off
 
::GOTO comment macro
set "[:=goto :]%%"
::brackets comment macros
set "[=rem/||(" & set "]=)"
 
::testing
echo not commented 1
 
%[:%
  multi 
  line
  comment outside of brackets
%:]%
 
echo not commented 2
 
%[:%
  second multi 
  line
  comment outside of brackets
%:]%
 
::GOTO cannot be used inside for
for %%a in (first second) do (
    echo first not commented line of the %%a execution
    %[%
        multi line
        comment
    %]%
    echo second not commented line of the %%a execution
)
With curly brackets:
 
@echo off
 
::GOTO comment macro
set "{:=goto :}%%"
::brackets comment macros
set "{=rem/||(" & set "}=)"
 
::testing
echo not commented 1
 
%{:%
  multi 
  line
  comment outside of brackets
%:}%
 
echo not commented 2
 
%{:%
  second multi 
  line
  comment outside of brackets
%:}%
 
 
for %%a in (first second) do (
    echo first not commented line of the %%a execution
    %{%
        multi line
        comment
    %}%
    echo second not commented line of the %%a execution
)
With parentheses:
 
@echo off
 
::GOTO comment macro
set "(:=goto :)%%"
::brackets comment macros
set "(=rem/||(" & set ")=)"
 
::testing
echo not commented 1
 
%(:%
  multi 
  line
  comment outside of brackets
%:)%
 
echo not commented 2
 
%(:%
  second multi 
  line
  comment outside of brackets
%:)%
 
 
for %%a in (first second) do (
    echo first not commented line of the %%a execution
    %(%
        multi line
        comment
    %)%
    echo second not commented line of the %%a execution
)
Mixture between powershell and C styles (< cannot be used because the redirection is with higher prio.* cannot be used because of the %*) :
 
@echo off
 
::GOTO comment macro
set "/#:=goto :#/%%"
::brackets comment macros
set "/#=rem/||(" & set "#/=)"
 
::testing
echo not commented 1
 
%/#:%
  multi 
  line
  comment outside of brackets
%:#/%
 
echo not commented 2
 
%/#:%
  second multi 
  line
  comment outside of brackets
%:#/%
 
 
for %%a in (first second) do (
    echo first not commented line of the %%a execution
    %/#%
        multi line
        comment
    %#/%
    echo second not commented line of the %%a execution
)COPY

CrLf

实际上用在 for 里效果并不好，一方面是效率低，另一方面是虽然没执行但照样需要符合预处理规则
所以对 for 和 if 来说，多行注释还不如用 if 1==2 ( 你的注释 )